Process and device for an open-loop control and a closed-loop control of a brake system of a vehicle

Abstract

A process and device for an open-loop control and a closed loop control of the brake system of a vehicle, wherein brake pedal actuation is measured by at least two, preferably diversitary, measuring devices, and the driver's braking command is independently obtained and further processed from at least two actuation signals. A third measuring device, measuring brake pedal actuation, is provided for locating errors. The control device effecting the open-loop control and the closed-loop control of the brake system comprises at least two microcomputers with the signals of the at least two measuring devices being supplied to both, while the signal of the monitoring device is only supplied to one microcomputer.

What is claimed: 
     
       1. A process for at least one of an open-loop control and a closed-loop control of a brake system of a vehicle having a computer system with at least two microcomputers, comprising the steps of: determining at least two actuation parameters corresponding to a brake pedal actuation by a driver;   performing at least one of the following steps: (a) determining a driver braking command in a computer system as a function of the at least two actuation parameters, the driver braking command being formed as a function of predefined relationships between the driver braking command and the at least two actuation parameters, the driver braking command being converted into setpoints for controlling wheel brakes; and   (b) identifying an error as a function of the at least two actuation parameters;     controlling the wheel brakes in at least one of an open loop and a closed loop as a function of the setpoints;   wherein at least one of the determination of the driver braking command, the determination of the setpoints, and the identification of the error is performed in each of the at least two microcomputers independently of others of the at least two microcomputers, the at least one of the determination of the driver braking command, the determination of the setpoints, and the identification of the error further being performed in each of two independent processing channels in one of the at least two microcomputers.   
     
     
       2. The process according to claim 1, wherein parameters corresponding to the driver braking command are compared to form a difference, and wherein the error is identified if the difference exceeds a predetermined value. 
     
     
       3. The process according to claim 1, wherein the driver braking command corresponds to a braking force having a braking parameter. 
     
     
       4. The process according to claim 1, wherein a first actuation parameter of the at least two actuation parameters corresponds to a pedal actuation force, and wherein a second actuation parameter of the at least two actuation parameters corresponds to a pedal path. 
     
     
       5. The process according to claim 1, wherein the at least two actuation parameters includes a further actuation parameter corresponding to a monitoring component, the error being identified as a function of the monitoring component. 
     
     
       6. The process according to claim 5, wherein the monitoring component redundantly measures a brake pedal actuation, and further comprising the steps of: forming a reference value as a function of actuation signals of the monitoring component corresponding to the driver braking command;   determining a further value based on the actuation signals of measuring devices;   comparing the reference value and the further value to form a component difference value; and   integrating the component difference value over a predetermined time interval to form an integral value, the integral value having an absolute value to indicate a lack of the error to be identified.   
     
     
       7. The process according to claim 5 wherein the monitoring component has at least one individual switch contact, and wherein the error is identified in a switch position of the at least one individual contact by comparing predetermined reference values with values derived from a measured signal. 
     
     
       8. The process according to claim 1, wherein the driver braking command includes default values determined when the error is identified. 
     
     
       9. The process according to claim 1, further comprising the steps of: predicting a first signal variation of a measuring signal of a measuring device; and   measuring a second signal variation of the measuring signal of the measuring device, the error being identified when the first signal variation differs from the second signal variation.   
     
     
       10. A device for at least one of an open-loop control and a closed-loop control of a brake system of a vehicle, comprising: a pedal measuring unit determining a pedal actuation by a driver and including at least two measuring devices, the at least two measuring devices determining at least two actuation parameters indicative of the pedal actuation; and   at least one electronic control unit including a computer system for determining a braking command and setpoints for controlling wheel brakes, the computer system controlling at least one of the open-loop control and the closed-loop control of the brake system, the computer system having stored relationships between the braking command and the at least two actuation parameters, the computers system forming the braking command as a function of the at least two actuation parameters and the stored relationships,   wherein the computer system includes at least two microcomputers receiving the at least two actuation parameters, each of the at least two microcomputers at least one of determining the braking command, determining the setpoints, and identifying an error, and wherein one of the at least two microcomputer performs the at least one of determining the braking command, determining the setpoints, and identifying the error redundantly in two independent software channels.   
     
     
       11. The device according to claim 10, wherein the pedal measuring unit further includes a monitoring component for identifying the error, the at least two measuring devices generating measuring signals provided to the at least two microcomputers, the monitoring component generating a monitoring signal provided to only one of the at least two microcomputers. 
     
     
       12. The device according to claim 10, wherein at least one of the measuring devices and the microcomputers forming the two channels are powered from independent power sources.